1. Field of the Invention
The present invention relates to the field of electrographic stylus recording apparatus capable of producing a toner powder image on a receptor belt and, more particularly, to such apparatus wherein the toner powder image is produced on a receptor recording belt with the toner powder reused for subsequent recording of a toner powder image.
2. Description of the Prior Art
U.S. Pat. No. 4,460,907 issued July 17, 1984 to Kerry S. Nelson discloses an electrographic stylus recording apparatus capable of producing an unfixed or nonpermanent toner powder image on a receptor belt. A stylus array is positioned adjacent to the receptor belt to provide a recording gap. The electrodes of the stylus are preferably comprised of magnetically permeable material and the toner powder used is magnetically attractable and electronically conductive. A magnetic field producing means disposed within a rotatable shell is disposed on opposite sides of the stylus array which causes toner powder presented to the recording gap to bridge between the recording belt and the end of each stylus in the array. Upstream of the magnetic field producing means toner powder is supplied by an applicator to the recording receptor belt for movement to the recording gap. A circuit is established from the applicator to the receptor by the toner powder carried by the applicator. The side of the receptor away from the applicator is connected to ground so that a d.c. voltage applied between the applicator and ground is effective to cause toner powder to be held to the receptor recording belt for movement with the belt to the recording gap. During movement from the applicator to the recording gap there is dissipation of the force holding the toner powder to the receptor recording belt. Such spacing of the toner applicator at a position remote from the recording gap is also used in other electrographic magnetic stylus recording apparatus such as U.S. Pat. No. 3,946,402 to Lunde and U.S. Pat. No. 4,402,000 to Fabel et al. Such remote placement of the toner applicator upstream of the stylus array places restrictions on the design of an electrographic magnetic stylus recording apparatus.